Variable capacity vane pump for oil burners



ct. i2, 1948. w. H. DE LANCEY VARIABLE CAPACITY JANE PUMP FOR OIL BURNERS 3 Sheets-Sheet 1 Filed Aug. 4, 1944 wlw n .Ng

llll

l INVENTOR @ffm/'27. fIM/cfr ATTNZgZ* Oct. 12, 1948.

w.y H. DE LANCEY VARIABLE CAPACITY VANE PUMP FOR OIL BURNERS 3 Sheets-Shea?l 2 Filed Aug. 4, 1944 y INVENTOR MnwlfZM/cfr BY *gf z g A OR EVS Oct 12, 1948- w. H. DE LANCEY 2,451,279

VARIABLE CAPACITY VANE PUMP FOR .OIL BURNERS Filed Aug. 4, 1944 3 Sheets-Sheet 3 l/ /3 A INVEN-ron l (/4 4@ f /4 7/ vom YS Pan-.erred Oct. 12, 1

orrics VARIABLE vCAPACITY VAN E PUMP FR OIL BURNERS Warren E. De Lancey, Springfield-Mass., assignor to Gilbert & Barker Manufacturing Company, Springfield, Mass., a corporation ot Massachusctts Application August i, 1944, serial No. 548,021

3 Claims. l

This invention vrelates to improvements in fuel supply units for oil burners.

More particularly, the invention provides a variable capacity pump for supplying liquid fuel at substantially the same rate as it is consumed by the burner and, accordingly, the unit can be made smaller and operated with less power than the units now in general use, where fuel is pumped at a rate many times that at which it is used and the greater part of the pumped oil is by-passed. No fuel need be by-passed in many installations served by the pumping unit of this invention. However, a constant but restricted by-pass is provided for priming purposes when the unit is used with a low-level tank. When the supply tank is above the level of the unit, this by-pass may readily be rendered ineffective.

One object of the invention is to provide a fuel supply unit for an oil burner having a variablecapacity pump in which the stator of the pump is reciprocable as a piston ina cylinder by the pressure of the pumped liquid and carries the burner cut-offA valve the latter being closed by spring pressure on the stator until the pressure of the pumped oil exceeds a predetermined value.

Another object of the invention is to provide a variable capacity pump in which the pump stator serves as a piston, being movable in its cylinder by pressure of the pumped oil acting against spring pressure and in which the pump stator is substantially balanced on one side against the inlet pressure and on the other side against the outlet pressure so that there is substantially no lateral thrust or pressure of the stator on its guidesto interfere with its freedom of reciprocation.

Another object of the invention is to provide a variable capacity pump having a casingI providing within it a cylinder, a. combined pump-stator and piston mounted in said cylinderand having a pump chamber with inlet and outlet ports, a pump rotor rotatable in said chamber, and a conduit connecting the outlet port to one end of said cylinder for acting directly on the stator as a piston to move the same to vary the pumping rate.

A further object of the invention is to provide a fuel supply unit for an oil burner in an end portion of the casing of a driving motor, such portion of the casing having fixed and removable end walls and between these walls a fuel reser- (Ci. 10S-120) 2 voir, containing a variable-capacity pump secured to the fixed wall-the latter having connections for a fuel supply pipe, a burner outlet pipe and a return pipe and passages from the several connections to the pump-the motor casing having inside it spring means which is adjustable from outside the motor casing and which acts on the stator of the pump in opposition to de pressure of the pumped oil to vary the capacity or pumping rate of the pump.

These objects and others will more particularly appear as the detailed description proceeds.

The inventionl will be disclosed with reference to the accompanying drawings, in which;

Fig. l is a sectional elevational view of a fuel supply unit, embodying the invention and shown as mounted in th'e casing of its driving motor;

Figs-2 and 3 are full-size cross sectional views taken on the lines 2 2 and 3 3 respectively. of Fig. 1;

Figs, 4 and 5 are fragmentary sectional views taken on the lines 4 4 and 5 5, respectively. of Fig. 3; v

Fig. 6 is a fragmentary sectional view taken in the line 6 6 of Fig. 2;

Fig. 7 is an enlarged fragmentary View taken similarly to Fig. 2 and showing :the pump more clearly and in greater detail; and

Figs. 8 and 9 are fragmentary sectional views taken on the lines 8 8 and 9 9, respectively of Fig. 7.

Referring to these drawings and rstto Fig. v1 thereof, the pumping unit of this invention is shown as mounted in one end portion of the casing of an electric motor which drives it. The stator of the motor is indicated at I, its windings at 2 and the encompassing casing at 3. The rotor is shown at i, fixed to the shaft 5, which,as shown, carries on one enda fan 6 for supplying air to the oil burner. The rotor has fixed thereto a plate 1, which carries the weight segments 8 of a speed-responsive couplingsuch segments being adapted to move outwardly by centrifugal force at a predetermined speed and engage the inner periphery of a drum 9, fixed as indicated, to the inner end of a pump driving shaft Il). This coupling may be of the type disclosed in my copending application Serial No. 530,107, led

April 8, 1944, now abandoned. The motor has a special end casing having a. cylindrical wall H f 3 and a transverse partition wall I2, subdividing its interior into an inner chamber, housing the speed-responsive coupling 8, 9, and an outer chamber housing the pump. This en d casing is suitably ilxed to casing 3 as by the bolts I2', indicated in Fig. 2.

The pump includes a casing h'aving an inner end plate I3, an outer end plate I4 and an intermediate plate I5. These plates are secured together, and clamped to a finished annular flat face I6 of wail I 2 by a plurality of cap screws l1, which thread into said wall. A pair of dowel pins I8, 'xed in said wall pass through the several plates and serve to hold the same in exact alignj ment. A gasket I 9 is interposed between plate I3 and the face I6 of wall I2 to seal the joint therebetween. In the wall I2 is a central hole to receive a pilot portion of a hub 2i which projects rearwardly into one end vof the motor casing and rotatably supports the pump shaft Ill. Slidably mounted on the inner portion of hub 2I is a seal ring 22, the inner end face of which is pressed by a spring 23against an end face 24 on the drum 9, as one means .to prevent the escape' of any liquid which may leak from the pump and pass between shaft I0 and hub 2I. A rubber packing ring 25 prevents leakage from the pump from passing into the motor casing between the hub 2I and seal ring 22.

The outer end of casing II is closed by a cover 26, having an annular flange 21 which engages an end face of such casing. The latter has an annular flange 28, grooved to receive a packing ring 29 which bears against the interior peripheral wall of ange 21 and makes the joint liquid tight. The cover is held in place by a cap nut 30, threaded on the outer end of a stud 3|, fixed to and projecting :outwardly from the outer plate I4 of the pump housing. A packing ring 32, mounted in a groove in stud 3|, at a point intermediate the ends of the latter, is compressed Abetween the stud and the wall of the central hole in cover 26 to prevent escape of liquid. The cap nut 30 sets into a recess in the cover 26 and a snap ring 33 is held in a groove in the wall of such recess and engages the outer face of a ilange 34 on the cap nut. This arrangement facilitates removal of the cover which is held tightly by pressure Iof the packing ring 29 on flange 21. By unscrewing nut 30, its flange 34 Will press against the snap ring 33 yand force oil' the cover, thus avoiding the prying oil" of the cover with tools as might otherwise be necessary. l

'I'he outer chamber in casing II-that space between the wall I2 and cover 26-forms a reservoir for the liquid fuel. This space is partitioned by a lter 36 of any suitable form. As shown, the lter is of porous metal. It has a central opening to closely Ifltstud 3| and its outer rim is confined within the annular flange 28 and is seated against an annular shoulder 31 on wall I2. The lter is held against such iiange by a spring 36'. There is a tapped hole 38 in the casing II forming a connection for a fuel inlet pi-pe (Fig 6). This hole 38 is connected by a diagonal passage 3B' to the inlet chamber 39, formed between the filter 36 and the cover 26. The space between the lter 36 and wall I2 forms a pump inlet chamber 40. The pump housing, above described, is located in this chamber 4B in a cylindrical recess formed in wall I2. The

pump housing is spaced from the circular wall of` such recess so that liquid can pass all around its marginal wall', as will be clear from Fig. 2.

The pump casing provides within it a cylinder in which is slidably mounted the combined pumpstator and piston 4I. This member 4I has parallei straight side walls 42 and 43 and a rightangularly disposed straight top wall 44. Its bottom wall consists of a short straight central portion 45, the ends of which are connected, lone to the adjacent end of the wall 42 and one to one side wall of the recess in plate I5 and there are upper and lower lands 49 and 56, projecting inwardly from the opposite side wall of such recess. The stator 4I slidably fits between the lands 41 and 49 and between the lands 46 and 50 and is free to move up and down but is confined against lateral movement.

The stator 4I is provided with a cylindrical l opening therethrough to receive the pump rotor.

l The latter comprises a cylindrical body 5I having o.. un

parallel flat end faces spaced apart by the same f distance as the end faces of the'stator so that it closely ts between the plates I3 and I4 but is free to rotate. The periphery of the body 5I is provided with a plurality (six as shown) of equally spaced radially-disposed slots 52 in which a. plurality of blades 53 are slidably mounted, one in each slot. These blades are forced outwardly so that their outer edges engage the inner peripheral wall 54 by hydraulic pressure as will later appear. The rotor has a central opening with keyways to receive the outer end of shaft I0 and opposite ends of a key 5'5 which passes diametrically through the shaft. I

The inner plate I3 (Figs. 3 and 5) of the pump housing has a passage 56 leading from the peripheral Wall of the plate upwardly. In the inner face of plate I3 is an arcuate groove 51 and forming an inlet port`` for the pump. This groove is coaxial with shaft I0, but located on one side thereof" and near the side wall 43. The lower end of groove 61 is connected to the vupper end of lpassage 56 by a hole 56. As will'be'clear from Fig. 7, liquid from the pump inlet chamber 40 can enter passage 56, hole 58 and groove 51, passing into the pockets between certain of the pairs of blades 53'. The rotor, travelling clockwise, carries each pocket successively out of communication with vgroove 51 and into communication with an arcuate groove 59 formed in the inner face of plate I3 on the opposite side of shaft I6. Groove 59 is connected by a hole 60 with a radial passage 6I in plate I3. Groove 59 forms an outlet port for the pump and is located near the side wall 42. Beyond the hole 60, groove 59 is enlarged, as at 59', to provide a free escapeof fluid from the rotor pockets just prior to their transition from the pressure to the y suction side of the pump. The outerv end of passage 6I is closed by a plug 62. A hole 63 in plate I3 connects passage 6I to the inner face of plate I3 at a location such as to deliver the pumped oil into the space l64, which is bounded by the lands 41 and 48, the wall 42 and the adjaf cent side wall of the cylinder. In the lower land 48 is a groove 6-5 (Fig. 8), so that liquidcan passv into the outlet space 66 between the three-sided Thel lower end of the stator-piston and the correspondingly-shaped lower wall of the cylinder.

Aisolformed in the inner face of plate I3 is a circular groove 61 which is coaxial with shaft I and is connected at one point by a hole 68 with the outlet passage. As will be clear from Fig. 7, this groove 61 constantly communicates with the bottom of each slot 52 in the rotor, whereby liquid under outlet pressure is lsupplied beneath the blades 53 to force them outwardly against wall 54. A similar groove 61 is in the inner face of plate I4, also interconnects the bottoms 'of the slotsI and helps in the distribution of the liquid to the several slots.

Liquid under inlet pressure is supplied through a passage 69 in the upper part of plate I6 which passage connects the pump inlet chamber 40 to the space between the top wall of the statorpiston and the adjacent top wall of the cylinder. The upper land 69 (Fig. 9) has a groove 1I therethrough which allows liquid under inlet pressure to flow into the space 12 between the side wall i3 and the adjacent side wall of the cylinder.

The edges of the keyway in shaft I Ii are bevelled as shown at 13 in Fig. 7. Four small channels are thus afforded through which liquid leaking radially inward between the plates I3 and i5 may pass to a drain channel 14 in plate i6 and be conducted into the pump inlet chamber 46. Leakage between the plates I4 and I5 will pass directly into this channel 16.

The outlet chamber 66 of the pump has an outlet passage 15, controlled by a needle valve 10. mounted on the lower end of the stator 4I. A tapped hole 11 (Fig. 1) is provided in the casing II for an outlet pipe to connect with the nozzle of the burner. This hole 11 is connected to the outlet 15 by a passage 'i8 in casing II and by a series of registering holes 19 in casing II, gasket I9, and plates I3 and I5. The valve 16 is mounted for adjustment in the stator 4I so that it .may adjust itself to the seat in the hardened bushing 80 in which the outlet passage 15 is formed.

In the lower end of stator 4I is a vertical opening BI in which the upper part of the stem of valve 'I6 is received together .with a spring 82, which encompasses the stem. The upper and pointed end of the stem of valve 16 is `received in the pointed center of the upper conical wall of the hole 8|. The upper end of this valve stem has a groove, in which a snap ring 83 is received,

and the spring presses against this snap ring and holds the point of the valve stem in the point of the hole 82. The spring is held in place by a plate 66, secured by screws 85 to the lower wall 65 of the stator and the valve stem passes freely through a central hole in this plate.

The stator 6I is held in its lower position and valve 16 isheld closed by a spring 86 acting between a xed but adjustablev spring seat 81 in casing i i and a seat 98. The latter is formed on top of a stem 89 which passes freely through the upper wall of the intermediate plate I '5 and has a pointed inner end which seats on the point of the conical bottom wall of a hole formed in the top wall of stator 4I. The upper part oi the spring 86 extends into a vertical hole 90 in casing II. The upper end of this hole is closed by a threaded cap 9I and sealed by a gasket 92. A stem 93 is rotatable in cap 9I and is sealed by a packing ring 94 in the cap. On this stem is a flange 95 abutting the bottom face of the cap 9|. i

On the stem, below the ange 95, is a screw 96 with which the spring seat 91 is lengaged as a nut. This seat 81 has diametrically opposed ears .91, projecting from its periphery and engaged the fuel supplytank. This hole 99 is connectedl by a passage |00 (Figfl) in casing I I to a passage IOI which is formed in casing II, gasket I9 and plate I4, and which4 opens into the outlet chamber 66. The passage IOI- hasintermediate its ends a restricted portion |02 which limits the amount of oil that can vpass therethrough. The arrangement affords a continually open by-pass from the pressure side of the pump to the fuel-supply tank. This by-pass is needed only when a low-level supply tank is used. If the supply tank is above the level of the pump, the hole 99 will be closed by y a pipe plug and the by-pass thus rendered inoperative. The sole purpose of thisA by-pass is to enable priming of the pump by the elimination of air from the pump and its suction line.'

In operation, when the coupling members 8 and 9 engage at the predetermined motor speed, the shaft I0 is rotated and with it the pump rotor 5I which revolves in a clockwise direction as viewed in Fig. 7. The pockets between adjacent blades 53 of the rotor become increasingly larger as they move downwardly from their uppermost to their lowermost positions and a partial vacuum is created to draw liquid from the supply tank through thesuction pipe into chambers 39 and 40 and through the'passage 56 and groove 51 into the pump. As the pockets between the blades travel upwardly from their lowermost to their uppermost positions, the pockets bec'ome increasingly smaller andliquid is forced outwardly by way of groove 59, passages 60, 6I and 63 into the space 64 and through groove 65 into outlet chamber 66. The valve 16 is initially closed `so there is no outlet for liquid except by way of the restricted by-pass I00, IOI, and |02. Consequently, pressure builds up in chamber 66 and. when the liquid reaches the desired predetermined pressure, the stator 4I moves upwardly, compressing spring 86 and opening the outlet valve 16 so that oil can ow to the nozzle of the burner. As the' the pressure drops, the stator will move down to increase the aforesaid relative eccentricity and the pumping rate. With the burner consuming oil at a constant rate, the pump will operate at a constant rate, and the stator will come to rest in a position wherein the force of liquid pressure on it balances the force of the spring on it. The rate of pumping automatically adjusts itself to the rate of oil consumption in any particular burner. For instance, if a larger nozzle is placed in the burner, the pump will automatically supply oil at such increased rate as is necessary. Except for the constant but restricted by-pass, no more oil is pumped than is consumed. And such bypass is not used except in connection with the so-called two pipe systems having a low level tank. With tanks located at a level above the burner, this by-pass is rendered inoperativeby screwing a plug into the return pipe connection 99.

It should be noted that the stator 4I of the pump serves also as the piston of a hydraulic cylinder, whereby-to move the stator directly by pressure of the pumped .liquid in order to vary'v the rate of pumping. `The stator also serves as and filter can be located in one end vof the casing of the driving motor without any apparent increase in length of the casing. I

Another important feature of the invention vis thatthe stator is balanced ,against the inlet and outlet pressures so that there is: no substantial lateral pressure on the guides, (in this case the several lands 41, 48, 69 and 50). The space 'i2 along one side of the stator is lled with liquid at inlet pressure, tending to thrust the -stator to the left. Such thrust is' substantially balanced by thethrust to the right due `to liquid at inlet pressure acting on the right hand curved part of the peripheral wallii ofthe pump chamber. The space 64 along the opposite side of the stator is filled with liquid at outlet pressure, tending to thrust the stator to the right. This thrust is substantially balanced by the thrust to the left due to liquid at outlet pressure acting on the lefthand curved part of the peripheral wall d of the pump chamber. Thus, there is substantially no lateral pressure of the stator on its guiding lands t1, 48, S9 and 50. Also, these are made of as small area as feasible. Thus, friction of the stator in its cylinder is reduced to a. very low figure, enabling .easy and free reciprocation ,of the stator. The space 10 above the stator is connected to the inletchamber for convenience. The

'I'he arrangement is exceedingly com'-l The invention provides a simple, compact construction of variable capacity pump which can readily be mounted in the casing of a small electric motor and operated therefrom with a small amount of power to supply fuel at a rate substantially equal to that at which it is consumed and at constant pressure.

I claim: e

l. A variable capacity pump', comprising, a casing having a cylinder formed by a peripheral wall and two parallel end walls, a pump stator Aslidably mounted in said cylinder.A and engaged with said end walls, said stator having a cylindrical opening therethrough, a cylindrical rotor mounted in said opening, the end faces of said rotor Lbeing rotatably engaged one with each of said end wallsfvanes movably mounted in the rotor and contacting the periphery of said opening, a drive shaft extending through one end wall into said opening and xed to said rotor, a spring f for moving said stator in said cylinder in one direction and tending to hold the stator in a position such that said opening and rotor are in ec# centric relation, said stator having top, bottom and two side walls and the peripheral wallof the cylinder including top, bottom and two side walls each spaced from the corresponding wall ofthe stator, and-inlet and outlet ports in said opening jacenty the outlet port, and means preventing tom wallsand the space between adjacent the inlet port.

2. A variable capacity pump, comprising, a casing having a cylinder therein with a top wall,

the side walls `a bottom wall, spaced parallel sidewalls and spaced parallel end walls, a pump stator having spaced parallel end Walls slidably engaged one with each of the end walls of said cylinder and having also a top wall, a bottom wall and two parallel side walls; each side wall on the stator beingv located parallel with but spaced from an adjacent side wall of said cylinder, said stator having a cylindrical opening therethrough forming a pump chamber, a pump rotor mounted in said chamber and .having end faces engaged one with each of the end walls of said cylinder, vanes movably mounted in the 'rotor and contacting the periphery of said opening, a driving shaft rotatably mounted in said casing and fixed to the rotor, pump inlet and outlet ports for said opening one near cach side wall of the stator, two longitudinally spaced lands on each cylinder side wall projecting inwardly and slidably engaging communication from the space between the botthe adjacent side wall of the stator; there being' -a space on each side of the stator bounded by the side wall of the stator, the adjacent side wall oi the cylinder, the twolands on such cylinder side wall and the two end walls of the cylinder; means for admitting liquid under inlet pressure to said spacenear the Vinlet port, means for admitting liquid under outlet pressure to said space near the o-utlet port, a spring for moving the-stator in one direction, and means for moving the stator in the other direction by liquid under outlet pressure.-

3. A variable-capacity rotary pump, compriss ing, a casing having a chamber, a member sildable in a straight line in said chamber, one portion of said member serving as a pump stator which has a cylindrical pump chamber formed therein, another portion of said member serving as a piston which is slidable in an end portion of said rst-named chamber, a cylindrical pump' rotor mounted inthe pump chamber, varies mov-4 ably mounted in the rotor and contacting the periphery of said pump chamber, a drive shaft for the rotor rotatably mounted in said casing and extending transverselyto the -direction of sliding movement of said member, said casing having an inlet and outlet leading to the pump chamber on opposite si'des of the rotor, the relative eccentricity of the rotor and stator determining the pumping rate, the outlet side of the pump chamber being connected to said end portion of e the first-named chamber, whereby to subject said piston directly to hydraulic pressure from the outlet side of the pump and move said member and the pump lchamber in a direction for decreas- I ing the pumping rate, means to apply spring (References on following page) 9 REFERENCES CITED The following references are 'of record in the le of this patent:

UNITED STATES PATENTS Number Name Date Parsons May 9, 1933 Kleckner July 23, 1935 Vincent Feb. 25, 1936 Wahlmark Feb. 7, 1939 Osborne Mar. 7, 1939 Number 10 Number Name Date Johnson Mar. 5, 1940 Weyenberg Jan. 21, 1941 Wagner J-une 24, 1941 McAJvay Sept. 21, 1943 Rohr et al Apr. 11, 1944 Taylor Dec. 5, 1944 FOREIGN PATENTS Country l Date Great Britain 1910 Netherlands Aug.' 15, 1930 

